对象深比较-蒲公英云

对象深比较

参考自：https://jsperf.com/deep-compare/4

Object.equals = function( x, y ) {
    if ( x === y ) return true;
      // if both x and y are null or undefined and exactly the same
    if ( ! ( x instanceof Object ) || ! ( y instanceof Object ) ) return false;
      // if they are not strictly equal, they both need to be Objects
    if ( x.constructor !== y.constructor ) return false;
      // they must have the exact same prototype chain, the closest we can do is
      // test there constructor.
    for ( var p in x ) {
      if ( ! x.hasOwnProperty( p ) ) continue;
        // other properties were tested using x.constructor === y.constructor
      if ( ! y.hasOwnProperty( p ) ) return false;
        // allows to compare x[ p ] and y[ p ] when set to undefined
      if ( x[ p ] === y[ p ] ) continue;
        // if they have the same strict value or identity then they are equal
      if ( typeof( x[ p ] ) !== "object" ) return false;
        // Numbers, Strings, Functions, Booleans must be strictly equal
      if ( ! Object.equals( x[ p ],  y[ p ] ) ) return false;
        // Objects and Arrays must be tested recursively
    }
    for ( p in y ) {
      if ( y.hasOwnProperty( p ) && ! x.hasOwnProperty( p ) ) return false;
        // allows x[ p ] to be set to undefined
    }
    return true;
  }